The present invention relates to a shift register and an electronic apparatus such as a display unit or an imaging apparatus, using this shift register as a driver.
In an active matrix type liquid crystal display such as a TFT liquid crystal display, each one line of display pixels arranged in the matrix form is selected, and display data is written in a pixel capacitance of the selected pixels, thereby obtaining desired display.
In the TFT liquid crystal display, there are used a gate driver for serially outputting a gate signal for pixel selection to a gate of the TFT functioning as a pixel switching device, and a drain driver for outputting a drain signal which serves as image data during a gate selection period in parallel. Since the drain driver which outputs usual moving image data must be constituted by multiple complex transistors and driven at a high speed, there is adopted a driver consisting of monocrystal silicon or polysilicon which can reduce the size of the transistors and has the high mobility.
On the other hand, since the structure of the gate driver is not very complicated as the drain electrode and the gate driver has a low driving frequency, it can be theoretically driven by a driver consisting of amorphous silicon TFTs but it has not been put into practical use.
Among the gate drivers constituted by multiple amorphous silicon TFTs, there are drivers having a threshold value characteristic of each TFT being shifted with a lapse of time, or those disadvantageously causing an erroneous operation in the high-temperature environment.